1646 ARBORETUM AND FRUTICETUM. PART III. 



whether this is not also only a variety of P. tremula, though he has 



made it a species. The specimen is of a female. 



The above varieties, we suppose, still exist on the ramparts of Bre- 

 men ; cuttings of them might, no doubt, be procured through the 

 Ploetbeck Nursery. 

 V P, /. 8 pendula, P. 'pendula- Lorfrf. Cat.,1836, and the plate of this variety 



in our last Volume, is the only distinct variety of P. tremula 



that exists in the neighbourhood of London. The handsomest 



specimen is at Kenwood, where a male plant, 8 years planted, is 



80 ft. high. 

 1 P. /. 9 suptna, P. stipina Lodd. Cat., ed. 1836, closely resembles the 



preceding sort ; and the plant in the Hackney arboretum is so very 



small, that it is difficult to say whether it is really distinct or not. 

 \ V.t. 10 laevigata ; P. laevigata Ait. Hort. Kew. y Lodd. Cat., ed. 183C ; 



has shining leaves, rather larger than the species. 



Description. A rapid-growing tree, rather exceeding the middle size, with 

 a straight clean trunk, tall in proportion to its thickness; and a smooth bark, 

 which becomes grey, and cracks with age. The branches, which extend 

 horizontally, and are not very numerous, become j 5 q 9 

 pendulous as the tree advances in age. The 

 young shoots are tough, pliant, and of a reddish 

 colour ; and both the wood and the leaves vary ex- 

 ceedingly, according to the dryness or moisture of 

 the soil in which the tree is grown. The flowers 

 appear in March, before those of any other poplar. 

 The roots, Sir J. E. Smith observes, creep and emit 

 suckers ; and these, as well as the young branch- 

 lets, are clothed with brown prominent hairs : they 

 are sometimes hoary, but not cottony. The coloui 

 of the upper surface of the leaves is a fine dark 

 glaucous shining green, and that of the under sur- 

 face of a paler shade. The disk of the leaf has a 

 small point, and 3 ribs; it is somewhat wavy, and 

 often shorter than the footstalk; which, being vertically compressed in its upper 

 part in relation to the plane of the leaf, counteracts the ordinary waving 

 motion of the leaf in the wind, and causes it to quiver with the slightest 

 breeze; whence has arisen the proverbial theme of comparison, the trembling 

 of an aspen leaf. {Smith in Eng. Ft.) The leaves, says Dr. Johnston of Ber- 

 wick, are of a fine smooth dark green, with a narrow yellowish edge, more or 

 less fringed with soft hairs, and suspended on flattened stalks; so that 



" When zephyrs wake, 



The aspen's trembling leaves must 6hake:" 



and, b\ their friction on one another, they make a constant rustling noise. 

 (/'"to ra of Berwick upon Tweed, vol. i. p. 2'30.) The tree, when in a suitable 

 -oil, grows with great rapidity during the first thirty years after being planted, 

 attaining, in that time, the height of from 60 ft. to 80 ft. ; afterwards, the trunk 

 increases slowly in thickness, and in 60 or 80 years it begins to decay, and can 

 seldom occupy the ground profitably for a longer period. When cut over 

 by the surface, the stool sends up shoots more freely than the white poplar, 

 but much less so than most other trees that stole. The want of shoots from 

 the stools, however, is amply made up by the abundance of root suckers. 



Geography t History, fyc, The trembling poplar is a native of most parts of 

 Britain! in wet soils. It is found as far north as Sutherland; at above 1 000 ft. 

 above the level of the sea, in liraemar, in Aberdeenshire ; and, at an elevation 

 of I ,00 it., in the Isle of Mull. It is indigenous to Ireland, in the county of 

 Dublin, and in other placet mentioned in Mackay's Flora J/ihcrnira. It is 



found, according to Mirbel, in the whole of the south of Europe, Asia 



Minor, and Caucasus, and in Lapland to the Frozen Ocean. It is very abun- 



